Conversion of Paper Waste Into Bioplastic (Poly-Lactic Acid)

摘要

The broadly apposite bioplastic, poly lactic acid was synthesized by using deinked paper waste as substrate, fermentation with Saccharomyces cerevisiae under controlled laboratory conditions followed by condensation polymerization. The substrate was initially subjected to acid hydrolysis followed by alkali neutralization to attain an ideal neutral pH for the growth of Saccharomyces cerevisiae. At regular intervals the amount of reducing sugar present in the samples were tested using 2,4-dinitrosalicyclic acid (DNS) method and the amount of sugar that was metabolized to alcohol and lactate were estimated using cerric ammonium nitrate and r-hydroxy biphenyl method respectively. The lactic acid extract was concentrated using a rotary vacuum evaporator and the amount was determined spectrophotometrically. The concentrated extract was used for polymerization in the presence of stannous chloride. This resulted in the production of white amorphous wafers. Polymerization trial with stannous chloride was done with 1ml of purified extract with 0.1 g of stannous chloride.